Fuel feeding mechanism for stokers



Oct. 18, 1949. R. E. BREssLER FUEL FEEDING MECHANISM FOR STOKERS Filed Jau. 25, 1945 Patented Oct. 18, 1949 UNITED STATES PATENT OFFICE FUEL FEEDING MECHANISM FOR STOKERS Robert E. Bressler, Oregon, Ill. Application January 25, 1945, Serial No. 574,518

12 Claims.

This invention relates to improvements infuel feeding mechanism for stokers and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

One of the objects of the present invention is to provide an improved mechanism for feeding fuel from a hopper to a stoker in such manner that a better agitation or stirring action is imparted to the fuel in the hopper, whereby arching of the fuel in the hopper is avoided and whereby a uniform flow or feeding movement of fuel from the hopper to the Stoker is assured.

Another object of the invention is to provide a fuel feeding mechanism of this kind wherein bowing f that part of the feed screw in the hopper is avoided and movement is imparted to the fuel over a greater part of the bottom of the hopper so as to avoid dead spots in and resulting packing of the fuel therein.

Furthermore, it is an object of the invention to provide in a fuel feeding mechanism of this kind, improved means for sweeping over a considerable area of the bottom of the hopper and whereby a better feeding action is possible by the feed screw.

The above mentioned objects of the invention, as well as others, together with the several advantages thereof will more fully appear as the specification proceeds.

In the drawing:

Fig. 1 is a plan view of the improved fuel feeding mechanism disposed in a hopper arranged in operative relation with respect to the associated stoker, the front wall of the furnace in which the burner of the stoker is located appearing in horizontal section.

Fig. 2 is a transverse vertical sectional view through a part of the fuel hopper and associated feed mechanism as taken on the line 2--2 and on the scale of Fig. 1.

Fig. 3 is a horizontal detail sectional View through a part of the improved feed mechanism as taken on the line 3-3 of Fig. 2, but on a scale enlarged thereover.

Fig. 4 is a detail vertical sectional view through a part of the improved feed mechanism as taken on the line 4 4 of Fig. 2 and on the scale of Fig. 3.

Fig. 5 is a perspective view of a certain sweep bar that is advantageously employed in the improved feed mechanism.

Referring now in detail to that embodiment of the invention illustrated in the accompanying drawing, I0 indicates the upright front wall of a furnace equipped with a stoker, only the dead plates II and the burner I2 of which appear in Fig. 1. A fuel duct or tube I3 extends from the 2 bottolm of the burner and opens through the front wall 0.

i4 indicates as a whole the bottom portion of a rectangularly shaped fuel hopper which includes front, rear and side upright walls I5, I 6 and I l--I'I respectively and a fiat bottom wall I8. As shown in Fig. 1, the hopper is square in plan and its rear wall is herein shown as abutting the front wall I0 of the furnace.

I 9 indicates a fuel feeding member in the form of a screw conveyor that includes a shaft portion 20 and a helical night portion 2|. This conveyor, which is arranged parallel with the side walls II-I'I is arranged oif center with respect to the bottom of the hopper and it extends from the front wall I5 of the hopper through the rear Wall I 6 and through the duct I3 and terminating in the bottom of the burner I2. The front end of the shaft portion 2D of the screw conveyor extends through the front wall I5 of the hopper and into the casing 22 of a gear reducing mechanism that includes a shaft 23 driven from any source of power such as a motor, not shown herein. The direction of drive of the screw conveyor, which is disposed only slightly above the bottom I8 og the hopper, is indicated by an arrow in Fig.

24 indicates an agitator which is journalled upon an upright stud 25 xedto and rising from the central portion of the bottom I8 of the hopper. This agitator includes an upright cylindrical body 26 of such diameter that its periphery has a slight clearance with respect to the periphery of the flight 2l of the screw conveyor I9, as best appears in Fig. 2. The body includes a central hub 21 that is journalled on the stud 25 and the bottom end of said hub has a part 28 of reduced diameter therein as appears in Fig. 2.

The bottom end of said body rests upon the bottom I8 of the hopper and the top end of said body has an outwardly extending radial flange 29. This flange over-hangs a part of the top peripheral portion of the flight 2I of the conveyor to hold it against upward bowing induced by the fuel as it is fed by said screw conveyor toward the end of the duct I3 communicating with the hopper, as before mentioned. In the mid portion of the body 26 are outwardly extending teeth 30 arranged to have a meshing engagement with the iiight 2l of the conveyor to be rotatively driven thereby. In the bottom' margin of the body-are oppositely disposed, downwardly opening recesses 3 I-3 I' as best appears in Figs. 3 and 4.

In Fig. 5 I have illustrated a sweep member 32 of a length greater than the diameter of the the bottom of the hopper in a agitator 2| and less than the width of the hopper from side to side or end to end. Said member is in the form of a dat ber including arms s3-u of a width approximating the cesses 3|-3I before mentioned and a central portion 34 of a. width greater than that of the arms. In said central portion is an opening 35 adapted to receive the part '28 of the hub o! the agitator as best appears in Fig. 2.

When the parts mentioned have been assembled into operative relation, said hub part 28 is disposed in the opening. 35 of the sweep member and parts of the arms 33-33 are disposed in the recesses 3I-3I in the bottom end of the body of the agitator. With the parts in this position, the sweep member engages fiatwise upon the bottom I I8 of the hopper land is capable of passing under the iiight 2| of the screw conveyor as best appears in Fig. 2. Thus the sweep member is so confined with respect to the agitator that it cannot be displaced therefrom but will be driven thereby so that the arms 33-33 will have a sweeping action over the bottom of the hopper and in the direction of the arrows shown in Fig. l. This direction is such as to sweep fuel toward the inlet of the fuel duct I3 and this materially aids the screw conveyor in feeding the fuel uniformly without voids into said duct. The sweep is further advantageous in thatit prevents fuel packing and arching above the screw conveyor and keeps good clean condition which aids fue1 movement therein. Also, with the structure described, that part of the screw conveyor in the hopper is held against upward bowing due to the feeding action of the fuel.

The construction described is simple and durable and will give eicient trouble-free operation in -feeding fuel to a stoker over a long peri od of time.

While in describing the invention I. have referred in detail to the form, arrangement and construction of the parts employed, the same is to be considered only in an illustrative sense so that I do not wish to be limited thereto except as may be specifically set forth in the appended claims.

I claim as my invention;

l. In a. fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, substantially horizontally disposed means for moving fuel from the hopper into and through said conduit, agitator means rotatively mounted on the hopper bottom, and a member rotative about the axis of said agitator means and located under said fuel moving means for sweeping over the bottom of said hopper.

2. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, substantially horizontally disposed means for moving fuel from the hopper into and through said'conduit, agitator means rotatively mounted on the hopper bottom, and a member rotative with said agitator means and located under said fuel moving means for sweeping over the bottom of said hopper, and for conveying fuel in a' horizonta1 direction toward said fuel moving means.

3. In a fuel feedingirrechanism for stokers, a

fuel hopper having a bottom, a fuel conduit leading from the hopper, a substantially horizontally disposed screw for moving fuel from the hopper into and through said conduit, agitator means rotatively mounted on the hopper bottom to one side of said screw, and a member disposed beneath .said screw and operatively connected to said 4 agitator-means to rotate therewith for sweeping over the bottom of the hopper.

4. In a. fuel feeding mechanism for stokers, a fuelhopper having a bottom. a fuel conduit leading from said hopper, a rotative screw arranged above and extending across a portion of the hopper bottom and having' a part disposed in said conduit for moving fuel therethrough, an agitator means including a cylindrical body rotatively mounted on a vertical axis on said hopper bottom y to one side vof the screw, a flange carried by said agitator means and extending laterally from the top thereof so as to overhang and be engageable by a. top peripheral portion of the screw for holding the same againstbowing under the action of the fuel being fed from said hopper toward said lconduit, and teeth extending radially from said body and having a driven engagement with one side :of said screw. f

5. In a fuel feeding mechanism for stokers, a fuel hopper-having a bottom, a fuel conduit leading from said hopper, a rotative screw extending across a portion of the hopper bottom and having a part disposed in said conduit for moving fuel therethrough, agitator means rotatively mounted on a, vertical axis on said hopper bottom .to one side of the screw and operatively driven thereby, and a radial flange on the upper end of said agitator means and extending laterally therefrom and overhanging anupper peripheral portion of the screw to hold the same against bowing upwardly under the action of the fuel being fed from said hopper toward said conduit.

6. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, means for moving fuel from the hopper into and through said conduit, agitator means, means rising from the hopper bottom and about which said agitator is rotatable,

. said agitator means having an upright skirt substantially engaged upon said bottom and which skirt has downwardly opening recesses in its bottom margin,and means including a plurality of sweep arms rotative-about said axis and having parts disposed in the recesses in said skirt to be rotative with said agitator for sweeping over the bottom of said hopper.

'7. In a. fuel feeding mechanism forstokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, means for moving fuel from the hopper into and through said conduit, agitator means, means rising from the hopper bottom and about which said agitator is rotatable, said agitator means having an upright skirt substantially engaged .upon said bottom, and which skirt has oppositely disposed downwardly opening recesses in its bottom margin, and means providing a bar extending across the bottom of said skirt and engaged in said recesses so as to be driven by said agitator in sweeping engagement over the hopper bottom.

8. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, a driven feed screw having one portion disposed in said conduit and another portion disposed in the hopper adjacent the bottom thereof, an vagitator rotatively mounted on the hopper bottom and having teeth engaged by the screw and whereby said agitator is rotatively driven by the screw,- a radial flange carried by the agitator and engageable by a part of the screw to prevent bowing thereof under the actionl of the fuel fed toward said outlet, and

means driven by said agitator and disposed under said screw for sweeping over the bottom of said hopper.

9. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduitl leading from the hopper, a driven feed screw having one portion disposed in said conduit and another portion disposed in the hopper adjacent the bottom thereof, an agitator rotatively mounted on the hopper bottom and having teeth engaged by the screw and whereby said agitator is rotatively driven by the screw, a radial ange on the upper end of said agitator and having a portion overhanging a part of said screw to hold the same against upward bowing under the action of the fuel fed to said duct, and means providine a plurality of arms disposed below the bottom of said screw and driven by said agitator means for sweeping over the bottom of said hopper.

10. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, a driven feed screw having one portion disposed in said conduit`and another portion disposed in the hopper adjacent the bottom thereof, an agitator rotatively mounted on the hopper bottom and having teeth engaged by the screw and whereby said agitator is rotatively driven by the screw, a radial ange on the upper end of said agitator and having a portion overhanging a part of said screw to hold the same against upward bowing under the action of the fuel feed to said outlet, there being recesses in the bottom of said agitator, and means providing arms rotative with said agitator and having parts disposed in `said recess and other parts disposed under said screw and which arms vsweep over the bottom of said hopper in the rotation of said agitator means.

11. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a fuel conduit leading from the hopper, a horizontally disposed feed screw having a portion disposed in the hopper adjacent but above the bottom thereof and adapted to supply fuel to said fuel conduit, a member mounted in the hopper adjacent said bottom for rotation about a vertical axis, said member having a portion overhanging and extending at least partway around a peripheral' top lpart of said feed screw for minimizing the bowing of the feed screw during fuel feeding operation, said member having radial teeth for a driven engagement with said screw.

12. In a fuel feeding mechanism for stokers, a fuel hopper having a bottom, a, fuel conduit leading from the hopper, a feedscrew having a portion disposed in the hopper adjacent the bottom thereof and adapted to supply fuel. to said fuel conduit, a member rotatively mounted in the hopper adjacent but above said bottom, said member having a cylindrical body with a top end radial flange portion overhanging a peripheral part of the feed screw from one side thereof for the purpose of minimizing an upward bowing of the feed screw during fuel feeding operation, and teeth extending radially from said body and having a driven engagement with said screw.

ROBERT E. BRESSLER.

REFERENCES CITED.

The following references are of record in the Ille of this patent:

UNrrED STATES PATENTS Numberl Name Date 1,302,922 Heylman May 6, 1919 1,444,648 Willis Feb. 6, 1923 1,659,254 Finger Feb. 14, 1928 1,720,398 Harrigan July 9, 1929 1,753,050 Hughes Apr. 1, 1930 1,812,911 Walter July 7, 1931 1,948,021 Burton Feb. 20, 1934 1,960,778 Goss May 29, 1934 FOREIGN PATENTS Number Country Date 456,908 Germany Apr. 5, 1924 

